Scientific Society Speaks Out on Climate.

• Author: Dunn, Seth

After months of internal discussion, the American Geophysical Union (AGU), a prominent international scientific body of 35,000 Earth and planetary scientists, made a bold move into the public global warming debate last January by unveiling a strongly worded position statement on climate change and greenhouse gases.

The move signifies a new political role for the high-profile body, which has traditionally distanced itself from any type of advocacy work by its members. It also marks the scientific group's first foray into environmental policy, as prior position statements have focused on research and education issues.

The paper reiterates several generally accepted fundamentals of climate change, including the role of humans in increasing levels of atmospheric carbon dioxide and other greenhouse gases, the link between enhanced greenhouse gas effects and rising surface temperatures, and the unusual increase in global temperatures over the last 150 years. It noted as well that "there is no known geologic precedent for the transfer of carbon from the Earth's crust to the atmosphere," in amounts comparable to fossil-fuel-burning, without simultaneous changes in the climate system.

The paper also addresses the relationship between climate science and policymaking. Present understanding of the Earth's climate, it argues, provides a "compelling...